1. Field of the Invention
The present invention relates to a liquid jet recording process where a liquid is ejected to form flying liquid droplets for recording.
2. Description of the Prior Art
Non-impact recording processes have recently drawn attention since the noise accompanying recording operation is negligibly small.
Among them, the ink jet recording process (liquid jet recording processes) which can effect high speed recording and can record on plain paper without fixation are very powerful processes. Heretofore, a wide variety of the systems and apparatuses therefor have been proposed. Some of them have been practically operated while others are now under development.
The liquid jet recording process disclosed in Japanese Patent Laid Open No. Sho 54-51837, Deutsch Offenlegungsschrift Nr. 2843064, U.S. Application No. 948236, filed Oct. 3, 1978, has a feature different from other liquid jet recording methods. The feature is that heat energy is applied to a liquid to produce an actuating force for ejecting the liquid.
The above-mentioned patent applications disclose a recording process in which a liquid causes a change of the state accompanying an abrupt increase in volume by application of heat energy and the actuating force due to the change of the state functions to eject liquid droplets from the orifice at the tip of a recording head and project the droplets to a record receiving member.
The liquid jet recording process of Deutsch Offenlegungsschrift Nr. 2843064 is effectively applied to the so-called drop-on-demand type recording process and moreover, the recording head can be easily constructed in the form of a high density multiorifice system of a full line type. As the result, images of high resolution and high quality can be produced at a high speed.
In this way, the above-mentioned liquid jet recording process has excellent features, but it is necessary for a higher speed recording of such images of high resolution and high quality that the number of the liquid droplets ejected from one orifice per unit time (N.sub.o) is increased.
In short, according to the above mentioned liquid jet recording process, bubbles are generated by a heat action and the abrupt increase and decrease of the volume causes the corresponding abrupt change of state and thereby, liquid droplets are projected from the orifice of the recording head to effect recording. It is necessary to increase N.sub.o by shortening the time for repeating the increase and decrease in volume (improvement in the liquid droplet ejection repeating property). It is proposed to increase the decaying speed of the increased bubble volume which is a rate controlling stage, for the purpose of improving said liquid droplet ejection repeating property. That is, the decaying curve of the bubble volume is made steep by a forced cooling to increase N.sub.o. The bubble is generated by heat from an electrothermal transducer transferred to a liquid in a heat actuating portion. For example, this may be carried out by following the procedures of Japanese Patent Laid Open No. Sho 54-51837 in which the heat actuating portion of a transducer and the liquid are forcibly cooled by a cooling means such as a Peltier element and the like.
However, when such a special cooling means is arranged at the recording head, the recording apparatus becomes complicated and expensive, and, in particular, such disadvantages are remarkable in case of a recording head of a multi-orifice type. Furthermore, in case of a recording head of a high density multi-orifice type, the result is far poorer since a high grade of precision technique is required for manufacturing such recording head from the view points of structure, processing and fabrication and therefore this results in a low yield, high cost and difficult maintenance.
Further, when the above mentioned cooling means is used to effect a forced cooling so as to accelerate reduction of volume of the generated gas, the cooling efficiency is low because the cooling of the bubble is carried out indirectly by cooling the liquid surrounding the bubble. The response of the cooling means is so slow that improvement in the repeating liquid droplet ejecting property is limited. If it is contemplated to increase the cooling velocity, it is necessary to excessively cool the liquid surrounding the bubble. This results in lowering of liquid droplet ejecting property and other disadvantages.
These disadvantages cause unstable supply of the liquid to the heat actuating portion in the recording head, non-uniform volume of ejected liquid droplets, non-uniform speed for ejecting liquid droplets, lowering of fidelity and accuracy of response to recording signals and like, lowering of recorded image quality, and stoppage or recording.